A052966 Expansion of (1-x)/(1-x-4x^2+2x^3).

1, 0, 4, 2, 18, 18, 86, 122, 430, 746, 2222, 4346, 11742, 24682, 62958, 138202, 340670, 767562, 1853838, 4242746, 10122974, 23386282, 55392686, 128691866, 303490046, 707472138, 1664048590, 3886957050, 9128207134, 21347938154

Offset

0,3

Links

Table of n, a(n) for n=0..29.

INRIA Algorithms Project, Encyclopedia of Combinatorial Structures 1038

Index entries for linear recurrences with constant coefficients, signature (1,4,-2)

Formula

G.f.: -(-1+x)/(1-x-4*x^2+2*x^3)

Recurrence: {a(1)=0, a(0)=1, a(2)=4, 2*a(n)-4*a(n+1)-a(n+2)+a(n+3)=0}

Sum(-1/79*(-1-36*_alpha+15*_alpha^2)*_alpha^(-1-n), _alpha=RootOf(1-_Z-4*_Z^2+2*_Z^3))

Maple

spec := [S, {S=Sequence(Prod(Union(Prod(Sequence(Z), Z), Z), Union(Z, Z)))}, unlabeled ]: seq(combstruct[count ](spec, size=n), n=0..20);

Crossrefs

Sequence in context: A152883 A285793 A117692 * A305135 A177248 A191706

Adjacent sequences: A052963 A052964 A052965 * A052967 A052968 A052969

Keyword

easy,nonn

Author

encyclopedia(AT)pommard.inria.fr, Jan 25 2000

Extensions

More terms from James A. Sellers, Jun 06 2000

Status

approved